Fixed the auto height bug by optimizing the reloading of sections.

Author: jeantimex

ios-swift-collapsible-table-section/CollapsibleTableViewCell.swift

@@ -30,6 +30,7 @@ class CollapsibleTableViewCell: UITableViewCell {
 
         // configure detailLabel
         contentView.addSubview(detailLabel)
+        detailLabel.lineBreakMode = .byWordWrapping
         detailLabel.translatesAutoresizingMaskIntoConstraints = false
         detailLabel.leadingAnchor.constraint(equalTo: marginGuide.leadingAnchor).isActive = true
         detailLabel.bottomAnchor.constraint(equalTo: marginGuide.bottomAnchor).isActive = true

ios-swift-collapsible-table-section/CollapsibleTableViewController.swift

@@ -89,7 +89,7 @@ extension CollapsibleTableViewController {
     }
 
     override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
-        return sections[section].items.count
+        return sections[section].collapsed ? 0 : sections[section].items.count
     }
 
     // Cell
@@ -145,12 +145,7 @@ extension CollapsibleTableViewController: CollapsibleTableViewHeaderDelegate {
         sections[section].collapsed = collapsed
         header.setCollapsed(collapsed)
 
-        // Adjust the height of the rows inside the section
-        tableView.beginUpdates()
-        for i in 0 ..< sections[section].items.count {
-            tableView.reloadRows(at: [IndexPath(row: i, section: section)], with: .automatic)
-        }
-        tableView.endUpdates()
+        tableView.reloadSections(NSIndexSet(index: section) as IndexSet, with: .automatic)
     }
 
 }